Unfortunately, there is no Lisp backtrace to be had, and I was unable to reproduce the crash. It is a segv during gc_sweep(). What I was doing was... I am goofing with a script that acts as a front end to XEmacs; it's similar to the one in the distribution that uses gnuclient or starts a fresh XEmacs session. I've got it testing to see if a "-display" option was passed or if $DISPLAY is set, and if neither is true, and we are on a tty, then it ommits the "-unmapped" argument, since XEmacs can't cope with that when stdin/out are not a tty and DISPLAY is not set somehow. I opened a terminal, unset DISPLAY, started a `screen', and then typed `xg', the name of my script. Since there was no response to the test for a running gnuserv, it started an XEmacs -f gnuserv-start. No problems. I flipped to another screen, and ran `xg' again. Boink, instant new frame. I can flip between them using the `screen' escapes. Next, I opened a second terminal, this time leaving DISPLAY set, and ran `xg'. Crash! I've tried it again several time, and cannot get it to crash again. When I run the gnuclient with DISPLAY set, it opens an X frame. There's a bug here though; that X frame is not initialized fully. The background is white, rather than the pixmap I have configured. Here's the bomb crater: bittersweet% gdb =xemacs core-20001102-00-48-43 GNU gdb 5.0 Copyright 2000 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i686-pc-linux-gnu"... Core was generated by `xemacs -f gnuserv-start'. Program terminated with signal 11, Segmentation fault. Reading symbols from /usr/X11R6/lib/libXaw3d.so.6...done. Loaded symbols for /usr/X11R6/lib/libXaw3d.so.6 Reading symbols from /usr/lib/libtiff.so.3...done. Loaded symbols for /usr/lib/libtiff.so.3 Reading symbols from /usr/lib/libpng.so.2...done. Loaded symbols for /usr/lib/libpng.so.2 Reading symbols from /usr/lib/libjpeg.so.62...done. Loaded symbols for /usr/lib/libjpeg.so.62 Reading symbols from /usr/lib/libz.so.1...done. Loaded symbols for /usr/lib/libz.so.1 Reading symbols from /usr/lib/libcompface.so.1...done. Loaded symbols for /usr/lib/libcompface.so.1 Reading symbols from /usr/X11R6/lib/libXpm.so.4...done. Loaded symbols for /usr/X11R6/lib/libXpm.so.4 Reading symbols from /usr/X11R6/lib/libXmu.so.6...done. Loaded symbols for /usr/X11R6/lib/libXmu.so.6 Reading symbols from /usr/X11R6/lib/libXt.so.6...done. Loaded symbols for /usr/X11R6/lib/libXt.so.6 Reading symbols from /usr/X11R6/lib/libXext.so.6...done. Loaded symbols for /usr/X11R6/lib/libXext.so.6 Reading symbols from /usr/X11R6/lib/libX11.so.6...done. Loaded symbols for /usr/X11R6/lib/libX11.so.6 Reading symbols from /usr/X11R6/lib/libSM.so.6...done. Loaded symbols for /usr/X11R6/lib/libSM.so.6 Reading symbols from /usr/X11R6/lib/libICE.so.6...done. Loaded symbols for /usr/X11R6/lib/libICE.so.6 Reading symbols from /lib/libdl.so.2...done. Loaded symbols for /lib/libdl.so.2 Reading symbols from /usr/lib/libdb2.so.2...done. Loaded symbols for /usr/lib/libdb2.so.2 Reading symbols from /usr/lib/libgpm.so.1...done. Loaded symbols for /usr/lib/libgpm.so.1 Reading symbols from /lib/libncurses.so.5...done. Loaded symbols for /lib/libncurses.so.5 Reading symbols from /usr/lib/libesd.so.0...done. Loaded symbols for /usr/lib/libesd.so.0 Reading symbols from /usr/lib/libaudiofile.so.0...done. Loaded symbols for /usr/lib/libaudiofile.so.0 Reading symbols from /lib/libm.so.6...done. Loaded symbols for /lib/libm.so.6 Reading symbols from /usr/lib/libpq.so.2.1...done. Loaded symbols for /usr/lib/libpq.so.2.1 Reading symbols from /usr/lib/libopenldap.so.1...done. Loaded symbols for /usr/lib/libopenldap.so.1 Reading symbols from /usr/lib/liblber-openldap.so.1...done. Loaded symbols for /usr/lib/liblber-openldap.so.1 Reading symbols from /lib/libutil.so.1...done. Loaded symbols for /lib/libutil.so.1 Reading symbols from /lib/libc.so.6...done. Loaded symbols for /lib/libc.so.6 Reading symbols from /lib/libcrypt.so.1...done. Loaded symbols for /lib/libcrypt.so.1 Reading symbols from /lib/ld-linux.so.2...done. Loaded symbols for /lib/ld-linux.so.2 Reading symbols from /lib/libnss_files.so.2...done. Loaded symbols for /lib/libnss_files.so.2 Reading symbols from /lib/libnss_dns.so.2...done. Loaded symbols for /lib/libnss_dns.so.2 Reading symbols from /lib/libresolv.so.2...done. Loaded symbols for /lib/libresolv.so.2 Reading symbols from /lib/libnss_compat.so.2...done. Loaded symbols for /lib/libnss_compat.so.2 Reading symbols from /lib/libnsl.so.1...done. Loaded symbols for /lib/libnsl.so.1 #0 0x403a2dc1 in kill () from /lib/libc.so.6 (gdb) where full #0 0x403a2dc1 in kill () from /lib/libc.so.6 No symbol table info available. #1 0x80c0033 in fatal_error_signal (sig=11) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/emacs.c:531 No locals. #2 0x403a2cf8 in sigaction () from /lib/libc.so.6 No symbol table info available. #3 0x8089c2f in gc_sweep () at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/alloc.c:3186 No locals. #4 0x808a2eb in garbage_collect_1 () at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/alloc.c:3506 speccount = 15 cursor_changed = 1 pre_gc_cursor = 143323096 gcpro1 = {next = 0xbfffea80, var = 0xbfffe97c, nvars = 1} #5 0x80c910f in Ffuncall (nargs=2, args=0xbfffea28) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/eval.c:3477 fun = 33 val = -1073747412 backtrace = {next = 0xbfffeb54, function = 0xbfffea2c, args = 0xbfffea30, nargs = 1, pdlcount = 0, evalargs = 88 'X', debug_on_exit = 2 '\002'} fun_nargs = 1 fun_args = (Lisp_Object *) 0xbfffea2c #6 0x8098afe in execute_optimized_program ( program=0x87d4db8 "Æ\016\036!ÇÈÇ\211\211É\036 \030\032\031\034\035\eÈ\024ÊË!«\021\016\013:«\f\016\013\022ÌÍ \n\"\021ª ÊÎ!«\027\016\016:«\022\016\016＠\016\016AÏE\022ÌÍ \n\"\021ª\005Ð\022Ï\021\013«s\013＠\025Ñ\r!«\aÒ\r!\020ª\rÓ\rÏÔ\r!\016!Z]\"\210Ñ\r!«\020Ì\b\n\"ÏV¬\017\tÔ\r!Wª\006Ô\r!ÏV«%Ñ\r!«\030\tÔ\r!W«\n\fÔ\r!\tZ^ª\r\fÔ\r!^ª\006\fÔ\r!^\024ª\024Ñ\r!«\aÕ\rÍ \"\210Ö\216×ØÙ\217\210)\013A\211\023¬\217\016\036\211\023«\016\fÔ\013＠!"..., stack_depth=1, constants_data=0x8544638) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/bytecode.c:746 n = 1 opcode = 33 program_ptr = ( Opbyte *) 0x87d4e09 "«\aÒ\r!\020ª\rÓ\rÏÔ\r!\016!Z]\"\210Ñ\r!«\020Ì\b\n\"ÏV¬\017\tÔ\r!Wª\006Ô\r!ÏV«%Ñ\r!«\030\tÔ\r!W«\n\fÔ\r!\tZ^ª\r\fÔ\r!^ª\006\fÔ\r!^\024ª\024Ñ\r!«\aÕ\rÍ \"\210Ö\216×ØÙ\217\210)\013A\211\023¬\217\016\036\211\023«\016\fÔ\013＠!^\024\013A\211\023¬ôÚÛ!\211\036\037«\fÜ\016\037!«\006\212Ý \210))\f.\a\207\001" stack_ptr = (Lisp_Object *) 0xbfffea28 speccount = 8 gcpro1 = {next = 0xbfffebd0, var = 0xbfffea28, nvars = 8} stack_beg = (Lisp_Object *) 0xbfffea24 stack_end = (Lisp_Object *) 0xbfffea44 #7 0x8098713 in funcall_compiled_function (fun=139713212, nargs=1, args=0xbfffeb8c) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/bytecode.c:518 value = 143537252 speccount = 7 i = 1 optional = 0 #8 0x80c94af in Ffuncall (nargs=2, args=0xbfffeb88) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/eval.c:3563 fun = 139713212 val = -1073747060 backtrace = {next = 0xbfffeca4, function = 0xbfffeb88, args = 0xbfffeb8c, nargs = 1, pdlcount = 7, evalargs = 0 '\000', debug_on_exit = 0 '\000'} fun_nargs = 1 fun_args = (Lisp_Object *) 0xbfffeb8c #9 0x8098afe in execute_optimized_program ( program=0x87d4d78 "\013?­&Æ\211\036\017\eÇ \034È\f\n\"\031É\035\f\022Ê\t!\025Ë\b!\210\r\026\020Ì\rÍÉÎ$\211\020-\207", stack_depth=1, constants_data=0x8546888) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/bytecode.c:746 n = 1 opcode = 33 program_ptr = ( Opbyte *) 0x87d4d90 "\025Ë\b!\210\r\026\020Ì\rÍÉÎ$\211\020-\207" stack_ptr = (Lisp_Object *) 0xbfffeb88 speccount = 2 gcpro1 = {next = 0xbfffecf0, var = 0xbfffeb88, nvars = 6} stack_beg = (Lisp_Object *) 0xbfffeb84 stack_end = (Lisp_Object *) 0xbfffeb9c #10 0x8098713 in funcall_compiled_function (fun=139713464, nargs=1, args=0xbfffecec) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/bytecode.c:518 value = 137546492 speccount = 1 i = 0 optional = 0 #11 0x80c94af in Ffuncall (nargs=2, args=0xbfffece8) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/eval.c:3563 fun = 139713464 val = -1073746708 backtrace = {next = 0x0, function = 0xbfffece8, args = 0xbfffecec, nargs = 1, pdlcount = 1, evalargs = 0 '\000', debug_on_exit = 0 '\000'} fun_nargs = 1 fun_args = (Lisp_Object *) 0xbfffecec #12 0x80cea62 in call1 (fn=0, arg0=11) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/eval.c:4183 ret_ungc_val = -1073748620 gcpro1 = {next = 0xbfffedc4, var = 0xbfffece8, nvars = 2} args = {139738956, 137546492} #13 0x8120257 in execute_internal_event (event=141287812) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/event-stream.c:3059 No locals. #14 0x8122559 in Fdispatch_event (event=141287812) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/event-stream.c:4232 console = 142714560 channel = 137546492 #15 0x80a7424 in Fcommand_loop_1 () at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/cmdloop.c:579 event = 141287812 old_loop = 137546492 gcpro1 = {next = 0xbfffee38, var = 0xbfffedc0, nvars = 1} gcpro2 = {next = 0xbfffedd0, var = 0xbfffedbc, nvars = 1} was_locked = 0 #16 0x80a76c2 in command_loop_1 (dummy=137546492) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/cmdloop.c:494 No locals. #17 0x80cf563 in condition_case_1 (handlers=137546588, bfun=0x80a7684 <command_loop_1>, barg=137546492, hfun=0x80a7734 <cmd_error>, harg=137546492) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/eval.c:1651 speccount = 0 c = {tag = 140544396, val = 137546492, next = 0xbfffef54, gcpro = 0x0, jmp = {{__jmpbuf = {137546492, -1073745820, -1073745596, -1073746180, -1073746428, 135066856}, __mask_was_saved = 0, __saved_mask = { __val = {134646706, 140262444, 3221221172, 1077400020, 1077339112, 3221221380, 3221221172, 0, 15, 3221221172, 15, 3221221148, 135898566, 3221221172, 1, 1073832140, 1077341016, 137725684, 0, 3221221156, 1077833123, 3221221140, 1073791465, 1073832140, 1077341016, 7, 0, 1077457233, 1077819789, 1078427080, 1073791294, 137546492}}}}, backlist = 0x0, lisp_eval_depth = 0, pdlcount = 0} gcpro1 = {next = 0x0, var = 0xbfffef14, nvars = 1} #18 0x80a7827 in command_loop_2 (dummy=137546492) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/cmdloop.c:256 No locals. #19 0x80cf42c in internal_catch (tag=-1073748620, func=0x80a77ec <command_loop_2>, arg=137546492, threw=0x0) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/eval.c:1317 c = {tag = 137622780, val = 137546492, next = 0x0, gcpro = 0x0, jmp = { {__jmpbuf = {137546492, -1073745820, -1073745596, -1073745908, -1073746124, 135066631}, __mask_was_saved = 0, __saved_mask = { __val = {3221221476, 3221221476, 3221221476, 3221221476, 3221221493, 3288330339, 3221221476, 3288330339, 0, 0, 0, 0, 0, 138410124, 12, 3221221356, 134217728, 3221221220, 16, 3221221372, 134775194, 140262444, 4294967295, 140262444, 3221221356, 3221221428, 1073791465, 1073832140, 1077341016, 7, 0, 3221221420}}}}, backlist = 0x0, lisp_eval_depth = 0, pdlcount = 0} #20 0x80a6c68 in initial_command_loop (load_me=0) at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/cmdloop.c:305 No locals. #21 0x80c106e in xemacs_21_2_b35_i686_bittersweet_linux () at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/emacs.c:2228 stack_bottom_variable = 0 '\000' skip_args = 0 load_me = 137546492 inhibit_window_system = -1073745820 #22 0x80c3082 in main () at /usr/local/src/PKG/woody/main/xemacs/xemacs/src/emacs.c:2657 vol_argc = 3 vol_argv = (char **) 0xbffff144 vol_envp = (char **) 0xbffff154 restarted = 0 #23 0x40393b8c in __libc_start_main () from /lib/libc.so.6 No symbol table info available.